No Wi-Fi upgrade for 20GB PS3
Not "currently" anyway.
Those of you hoping to buy the cheaper, 20GB PlayStation 3 and then upgrade its hard disk and network functionality at a later date may be bang out of luck - there's currently no way to get Wi-Fi into PS3 unless it's there out of the box.
That's according to a Q&A posted on Sony's Japanese PlayStation 3 website, partially translated by IGN. The offending question asks, "Can you expand the 20GB model with Wireless LAN after purchase?" and the answer is "Not currently."
Of course, fixing that wouldn't be a big deal - the PS3's understanding of all things USB, and Sony's capacity to upgrade the onboard operating system through PSP-style firmware updates, allows for some sort of aftermarket compatibility patch.
But with wireless PSP connections as well as wireless Internet access blocked off until they do, it's not something you'd necessarily want to bet on, even if the difference in price (the 60GB PS3, with Wi-Fi built in, costs another EUR 100) is otherwise tempting.
